It is known to make food products comprising a biscuit part and a filling part. It is also known for these food products to include in the filling part a water-based filling and an anhydrous filling with live lactic cultures. Anhydrous fillings comprising live lactic culture are usually produced with yoghurt.
Yoghurt is the product of milk fermentation by symbiotic cultures of Streptococcus thermophilus and Lactobacillus delbrueckii subspecies bulgaricus. Yoghurt is known to have beneficial properties, such as facilitating lactose digestion. These beneficial properties arise from the presence of the two strains of bacteria in large quantities: in particular, the yoghurt has a total cell count of the population of both strains of over 107 cfu/g (cfu: colony-forming unit). However, the shelf-life of yoghurt is usually short; usually less than 2 months for fresh yoghurt. Therefore, yoghurt is usually kept at low temperature to limit decay of lactic cultures and organoleptic properties modification.
It is known to make yoghurt powders since they have a longer shelf-life with respect to the organoleptic properties. They are obtained via various drying methods such as freeze-drying and spray-drying. For economic reasons, spray drying is more commonly used. However, spray-drying is more detrimental to lactic culture survival than freeze-drying during production and, thus, results in a greater loss of lactic cultures during drying. Consequently, most of the commercially available yoghurt powders only contain limited amounts of live lactic cultures; lower than 107 cfu/g of yoghurt powder. These are, moreover, not sufficiently viable during storage.
Food products currently on the market that comprise a biscuit part and a filling part, with an anhydrous filling comprising live lactic cultures (yoghurt filling), use yoghurt powders obtained from spray-drying. Their live lactic culture cell counts (hereafter cell count) are therefore lower than the value required by Codex Alimentarius (CODEX STAN 243-2003). The inventors measured the cell count values for various commercially available food products comprising a biscuit part and a filling part. Results showed that cell count values were all under 105 cfu/g for the yoghurt filling, except for products using the method of FR2895877.
FR2895877 provides a method for producing yoghurt powder with high amount of live lactic cultures, i.e. higher than 5×105 cfu/g of yoghurt powder. This yoghurt powder can be used in fillings for producing sandwich biscuits with a high cell count.
The inventors have realised that a food product comprising a biscuit part and a filling part could provide both a pleasant slightly acidic taste due to lactic cultures and another taste such as fruit. Although such food products exist, these products' cell count values are lower than 105 cfu/g of anhydrous filling.
The use of the yoghurt powder produced according to FR2895877 was trialled by the inventors in an anhydrous filling incorporated into a food product together with a water-based filling. However, when the anhydrous filling comprising the yoghurt powder of FR2895877 was put into direct or indirect contact with a water-based filling, decay of live cultures was strongly accelerated. In this trial, 10 wt. % of yoghurt powder, 80 wt. % glucose syrup and 10 wt. % fat were mixed in order to obtain a water-based filling. The Aw of the filling was 0.70. The filling was stored at 20° C. The initial cell count was 8.5 log10 cfu/g of filling and decreased down to 6.5 log10 cfu/g of filling after only 1 month. The same fast decay was obtained with fillings with Aw of 0.60, 0.65 and 0.75. It was therefore not possible to keep the cultures alive for several months using a water-based filling at intermediate moisture.
WO 99/11147 A1 describes a food composition where the cream is deposited on one or more biscuit layers.
WO 2011/113771 A1 describes a dried fermented dairy product.
EP 0 948 896 A1 describes a cream filling for bakery products.
EP 1 269 857 A2 describes a filling for bakery products comprising yogurt powder.
FR 2 811 867 A1 describes a baked product with a filling comprising live or active yeast.
EP 1 010 372 A2 describes a baked good with a filling comprising live lyophilized lactic bacteria.
WO 99/09839 A1 describes a paste-like composition containing live microorganisms.
EP 0 666031 A2 describes a cream filling for bakery products based on anhydrous food fats.
EP 0 687 420 A2 describes a filling for bakery products.
FR 2 895 877 A1 describes a powder of fermented milk or of yogurt.
Therefore, one aim is to provide a food product comprising a biscuit part and a filling part, the filling part of which comprises a water-based filling and an anhydrous filling with live lactic cultures, that tackles the drawbacks associated with the prior art, or at least provides a commercial alternative thereto.
According to a first aspect, there is provided a food product comprising a biscuit part and a filling part, the filling part including a water-based filling and an anhydrous filling with live lactic cultures, wherein the water-based filling and the anhydrous filling are distinct, and wherein the anhydrous filling has a lactic cultures cell count of at least 105, preferably 106, more preferably 107 cfu per gram of the anhydrous filling. The food product presents a decay rate of the lactic cultures of at most 0.25 log10 cfu/g of anhydrous filling per month.
The present disclosure will now be described further. In the following passages different aspects/embodiments of the disclosure are defined in more detail. Each aspect/embodiment so defined may be combined with any other aspect/embodiment or aspects/embodiments unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.
The food product can be a layered biscuit, preferably a sandwich biscuit or a single biscuit with filling lying on one surface thereof. The food product can also be a filled biscuit, the edges of which are closed.
In the following specification, “biscuit part” means any baked cereal products, with a low moisture content (less than 5%) and a crispy texture, made from a dough or a batter, that includes the commonly known biscuits, cookies, crackers, wafers, and backed granola bars, preferably biscuits, cookies, crackers and wafers. The biscuit part can consist in only one, two or more biscuits. When there is only one biscuit, the filling part can be deposited wholly onto one surface thereof or partially on each surface. The filling part can also be deposited inside the biscuit. When there are two or more biscuits, the filling part may be layered between two biscuits.
The biscuit part may also contain inclusions, i.e. small pieces of edible particles with a size lower than 4 mm. Inclusions may be chocolate drops, nuts like hazelnut (preferably hazelnut pieces), extruded cereal, etc. Inclusions do not include cereal flakes. Inclusions bring texture and flavour without increasing SAG content. The food product advantageously comprises 2 wt. % to 15 wt. % inclusions, preferably 4 wt. % to 10 wt. %.
Chocolate drops are pieces of solid chocolate. “Chocolate” is understood as meaning either “dark chocolate”, “milk chocolate” or “white chocolate”. Preferably, chocolate drops are dark chocolate pieces containing at least 35 wt. % of cocoa liquor (US legislation), more preferably 35 wt. % of cocoa solids (European Union legislation), still more preferably at least 40 wt. %.
“Filling part” means any edible substance that is suitable for being placed inside or onto a biscuit or between the layers of a sandwich biscuit. The filling part consists in at least two different fillings with different compositions.
“Water-based filling” is a filling, wherein water forms a continuous phase throughout the whole filling, with contrast to “anhydrous filling”, wherein fat forms a continuous phase throughout the whole filling. In a preferred embodiment, the water-based filling and the anhydrous filling directly contact each other.
By “distinct” it is meant that the water-based filling and the anhydrous filling have different compositions and can be differentiated in the final food product, either visually or organoleptically. Preferably the water-based filling and the anhydrous filling are physically distinct. That is, although they may be in contact, they form separate layers or structures within the food product. For example, the water-based filling and the anhydrous filling may form separate lines, perhaps lying parallel to each other between two biscuit portions.
“Lactic culture” means any bacteria suitable for producing fermented food product yielding lactic acid. These bacteria are chosen amidst the genus of Lactobacillus, Lactococcus, Streptococcus and Bifidobacteria. Examples of Lactobacillus are L. acidophilus, L. delbrueckii, L. kefiri, L. helveticus, L. salivarius, L. casei, L. curvatus, L. plantarum, L. sakei, L. brevis, L. buchneri, L. fermentum and L. reuteri. One example of Lactococcus is L. lactis. One example of Streptococcus is S. thermophilius. Examples of Bifidobacteria are B. bifidum, B. longum and B. infantis. 
In one preferred embodiment, if the anhydrous filling comprises yoghurt, then the lactic culture is a blend of L. delbrueckii and S. thermophilus, more preferably L. delbrueckii, subsp. bulgaricus and S. thermophilus. 
As will be appreciated, the anhydrous filling has a lactic cultures cell count which is preferably measured at the point of production of the food product. This allows the decay rate of the lactic cultures to be measured over time relative to the initial levels achieved when the product is produced and has been packaged. Moreover, the measurement of the decay rate is performed on sealed products stored at about 20° C. The rate can be measured over a period of at least 4 months, preferably at least 6 months, preferably at least 7 months, and the decay rate determined.
The water activity (Aw) of a product is a notion which is well known in the food industry field. This value measures the availability of water in a sample. In most cases, this water activity is not proportional to the water content of the product. Methods for measuring Aw of a product are known to the person skilled in the art. For example, it can be measured with an Aqualab CX-2 or series 3, or a Novasina. All Aw values indicated hereafter are measured at 25±0.2° C.
The overall Aw value of the food product is preferably lower than 0.22, preferably lower than 0.20, more preferably lower than 0.18. The biscuit part preferably has a water activity value lower than 0.15, preferably lower than 0.10, more preferably lower than 0.07. The water-based filling preferably has a water activity value lower than 0.45, preferably lower than 0.40, more preferably lower than 0.37. The anhydrous filling preferably has a water activity value lower than 0.35, preferably lower than 0.30, more preferably lower than 0.25. The anhydrous filling preferably comprises yoghurt, for example in a powder form.
The inventors have found that the water activity of the biscuit part and the filling part should be carefully managed to meet the above mentioned values, otherwise lactic cultures will decay at a rapid pace during storage. It should be mentioned that the overall water activity value of the food product cannot be directly computed from the water activity values of the biscuit part, the water-based filling and the anhydrous filling. Indeed, although the driving force for water migration is the Aw gradient, the final overall water activity value depends on water content of each component of the food product and on the extent to which moisture migration will take place. This cannot be simply predicted, especially when two different fillings and a biscuit part are put in contact.
The water-based filling preferably comprises fruit. In this case, the water activity value of the water-based filling can be decreased by concentrating the fruit juice or pureeing the fruit and eventually adding water-activity depressors such as sugars and/or polyols.
The inventors have surprisingly found out that with a biscuit part and filling part having the foregoing water activity values, it was possible to keep the lactic cultures alive during production and storage for a long period of time (at least 4 months, preferably at least 6 months at 25° C.).
The water-based filling, as already mentioned before, can comprise fruit. Moreover, the term “fruit” is here intended to mean any “natural” fruit excluding the dry fruits commonly called “nuts” (such as walnuts, hazelnuts, almonds, peanuts, cashew nut, pecan nut). Advantageously, the fruit is orchard fruit, more advantageously chosen in the group consisting of red fruit such as strawberries, raspberries, blueberries, blackcurrant, redcurrant, cranberry, elderberries or blackberries, exotic fruit such as pineapple, mango, passion fruit, pomegranate, litchi or kiwi, melon, peach, apricot, banana, cherries, apples, pears, citrus fruit such as orange, lemon, grapefruit, citrus or clementine, grapes, plums, cherry, Mirabelle, figs, raisin, tomato, carrot, red bell pepper, pumpkin, dates, and mixture thereof, still more advantageously chosen in the group consisting of cranberry, apricot, apple, raspberry, strawberry, raisin, peach, fig, dates, cherries, plums, tomato and mixture thereof, more advantageously chosen in the group consisting of cranberry, apricot, apple, raspberry, strawberry, raisin, fig and mixture thereof. By extension, Rhubarb is also included in the term “fruit”, even though it is not a botanical fruit, since it is usually classified and used as a fruit in cooking.
The fruit contained in the water-based filling can contain soft fruit particles, in which case, the maximum size of the soft fruit particles is 4 mm.
The water-based filling may contain cooked fruit such as jam. Alternatively, the water-based filling may contain fresh or preserved fruit.
Further, the water-based filling may contain any extract of cocoa, coffee or tea. The water-based filling may be aerated or foamed, preferably to obtain a density (mass per unit volume) between 300 g/l and 1200 g/l. The foamed or aerated form of the water-based filling makes it possible to improve mouthfeel, i.e. the water-based filling is less sticky in the mouth.
Both anhydrous and water-based fillings can contain ungelatinised starch, especially wheat starch, such as described in FR2889650 (anhydrous filling) and FR2905563 (water-based filling). The presence of ungelatinised starch can improve the slowly digestible starch (SDS) content of the final product.
The food product preferably has a slowly-digestible-starch-over-total-available-starch ratio (SDS/(SDS+RDS)) of at least 31 wt. %, preferably at least 35 wt. %, more preferably at least 38 wt. %, still more preferably at least 40 wt. %. Total available starch comprises slowly digestible starch (SDS) and rapidly digestible starch (RDS). The difference between total available starch and total starch is that total available starch does not comprise resistant starch that cannot be digested, i.e. that escapes digestion in the small intestine.
Consumption of slowly digestible starch in place of rapidly digestible starch is believed to be beneficial for health. Indeed, rapidly digestible starch is rapidly broken down into glucose during digestion and thus rapidly made available to the body. Therefore, the fast appearance of glucose from biscuits in the blood leads to a higher peak of glycaemic response. On the contrary, slowly digestible starch is slowly assimilated by the body due to an appearance of glucose from food products that is slower and maintained over time, thus providing long-lasting energy.
SDS or slowly available glucose (SAG) can be characterised through the slowly available glucose (SAG) measurement by Englyst method (“Rapidly Available Glucose in Foods: an In Vitro Measurement that Reflects the Glycaemic Response”, Englyst et al., Am. J. Clin. Nutr., 1999 (3), 69(3), 448-454; “Glycaemic Index of Cereal Products Explained by Their Content of Rapidly and Slowly Available Glucose”, Englyst et al., Br. J. Nutr., 2003(3), 89(3), 329-340; “Measurement of Rapidly Available Glucose (RAG) in Plant Foods: a Potential In Vitro Predictor of the Glycaemic Response”, Englyst et al., Br. J. Nutr., 1996(3), 75(3), 327-337). SAG refers to the amount of glucose (from sugar and starch, including maltodextrins) likely to be available for slow absorption in the human small intestine. In the present case, the SDS content equals the SAG content since there is no other SAG source than starch, i.e. SDS. Rapidly available glucose (RAG) refers to the amount of glucose likely to be available for rapid absorption in the human small intestine. RAG content is composed by the rapidly digestible starch and the glucose units provided by sugars included in the recipe. In Englyst method, biscuit samples are prepared by manually and roughly grinding one or more biscuits. The biscuit samples are then subjected to an enzymatic digestion by incubation in presence of invertase, pancreatic alpha-amylase and amyloglucosidase under standardised conditions. Parameters such as pH, temperature (37° C.), viscosity and mechanical mixing are adjusted to mimic the gastrointestinal conditions. After an enzymatic digestion time of 20 min, glucose is measured and is labelled RAG. After an enzymatic digestion time of 120 min, glucose is again measured and is labelled available glucose (AG). SAG is obtained by subtracting RAG to AG (SAG=AG−RAG), thus, SAG corresponds to the glucose fraction released between the 20th and the 120th minute. Free glucose (FG), including the glucose released from sucrose, is obtained by separate analysis. RDS is then obtained as the subtraction of FG from RAG (RDS=RAG−FG).
Advantageously, the food product has at least 15 g SAG/100 g food product. This food product particularly complies to long-lasting energy criteria, i.e. SAG value over 15 g/100 g biscuit or slowly-digestible-starch-over-total-available-starch ratio of at least 31% with respect to the total weight of the food product. Preferably, the food product has a SAG content of at least 16.5 g/100 g biscuit, more preferably at least 18.0 g/100 g food product, still more preferably at least 21.0 g/100 g food product.
The decay rate of the live cultures in the food product at 25° C. is lower than 0.25 log10 cfu/g of the anhydrous filling per month, preferably lower than 0.20 log10 cfu/g per month, more preferably lower than 0.15 log10 cfu/g per month. The values are related to a gram of anhydrous filling.
According to a further aspect, there is provided a method for producing the food product described above. The method comprises the following steps:                (a) providing a first biscuit forming at least a portion of the biscuit part, presenting a water activity value lower than 0.15, preferably lower than 0.10, more preferably lower than 0.07;        (b) depositing a water-based filling onto the first biscuit presenting a water activity value lower than 0.45, preferably lower than 0.40, more preferably lower than 0.37;        (c) cooling until the first filling cools down to 47° C. or lower, preferably higher than 20° C.;        (d) depositing an anhydrous filling with live lactic cultures onto the first biscuit or onto the first filling;        (e) optionally, providing a second biscuit forming another portion of the biscuit part on top of the filling part, presenting a water activity value lower than 0.15, preferably lower than 0.10, more preferably lower than 0.07, preferably at a temperature of 32° C. or lower, more preferably higher than 20° C.; and        (f) optionally cooling the food product down to 23° C. or lower, preferably higher than 10° C. before packaging.        
As described above, the water-based filling and the anhydrous filling are separately deposited on the biscuit part and at different temperatures. The deposition temperature of the water-based filling is higher that the deposition temperature of the anhydrous filling. This makes it possible to keep the lactic cultures alive during production. Indeed, the water-based filling, when cold, is a thick paste and cannot be processed at room temperature, especially in the case of a fruit-containing water-based filling to which water activity depressors are added. Thus, it becomes necessary to heat the water-based filling at a temperature as high as 50° C., or above, in order to be able to pump it and deposit a pre-set weight thereof onto the first biscuit. Heat is detrimental to live cultures, which are temperature sensitive.
The water-based filling is preferably heated to at least 45° C. before depositing, preferably 50° C., more preferably about 55° C. More in general, the water-based filling is heated to a temperature at which its viscosity reaches down to at most 54 Pa·s, preferably at most 45 Pa·s, more preferably at most 37 Pa·s. Techniques for measuring viscosity of such foodstuffs are well known in the art.
The anhydrous filling is preferably deposited at a temperature of 42° C. or lower, preferably at 39° C. or lower, more preferably higher than 37° C. More generally, the anhydrous filling is preferably heated to a temperature at which its viscosity reaches down to at most 13.5 Pa·s.
Step (a) and step (e) can comprise forming the first biscuit out of a dough, baking the first biscuit and cooling the first biscuit down to 35° C. or lower, preferably at 33° C. or lower, preferably higher than 20° C., before the water-based filling is deposited.
In order to obtain first, and eventually, second biscuits with a very low water activity value, it is possible to increase baking time thereof: this leads to the evaporation of more moisture. However, care should be taken so that gelatinisation of starch does not occur. Indeed, increased baking will creates a potential issue on starch structure preservation, what is required for keeping it slowly digestible. It also increases the gradient of water activity between the water-based filling and the biscuit, what could result in potential breakage or checking (checking refers to local cracking of biscuits occurring after baking, sometimes 2 weeks later. It can be visible or not and can lead to biscuit break during transport, storage or consumption). Increasing baking time also increases production cost, can generate product browning, various off-tastes (burnt flavour) and generate neo-formed compounds such as acrylamides.